Preparation, Drying And Application Of Micro-encapsulated Tetrabromobisphenol A Bis(2, 3-dibromopropyl Ether)

In this paper, micro-capsulation of flame retardant tetrabromobisphenol A bis(2,3-dibromopropyl ether) (TBAB), and the dryness of resulted micro-encapsulated TBAB are studied. Furthermore, the flame retarded properties of micro-encapsulated TBAB in extruded polystyrene foams are also investigated.In the process of micro-encapsulation, melamine was initially reacted with formaldehyde to form pre-polymer which was then cross-linked in-site in the surfaces of TBAB powders by so called in-situ polymerization method. The better parameters of preparation of micro-encapsulation were determined also. Firstly, pre-polymer should be formed when pH value was controlled at 7-8, and then was reduced gradually to 3-4 during the coating process. At the same time, in-situ polymerization reaction temperature should be risen slowly from room temperature to 80℃.Drying process of original TBAB and micro-encapsulated TBAB were investigated under conditions of different temperature and air speed. Drying speeds for both original TBAB and micro-encapsulated TBAB were measured. Results showed that shorter drying time and better drying effect could be obtained,when drying temperature was kept at 55℃and air speed of dryness was kept at 6m/s, respectively.The structure and performance of micro-encapsulation TBAB were characterized by XPS, Fourier-Transform Infrared Spectroscopy (FTIR) and TEM measurements, which all gave the positive evidence that TBAB powders had been coated completely. The thermal stability of TBAB had been improved greatly, and the thermal decomposition temperature could be increased from 160℃for TBAB core to 240℃for micro-encapsulated TBAB.Application of micro-encapsulated TBAB in flame retarded extruded polystyrene was studied. Test results of oxygen index and flame spread all proved that its high flame retardant efficiency in extruded polystyrene was preserved.